Stone Weight Calculator
Mass per square metre and total for stone slabs by density.
Quick answer
With the default inputs: Length 600 · Width 300 · Thickness 20 etc.Total mass 486.00 kg
Edit the inputs below to recalculate.Inputs
Result
Total mass
486.00kg
| Area per piece | 0.1800m² |
| Volume per piece | 0.00360m³ |
| Mass per piece | 9.72kg |
| Total area | 9.000m² |
| Total volume | 0.180m³ |
| Mass per m² | 54.00kg/m² |
| In tonnes | 0.486t |
| Pieces per tonne | 102.9pcs/t |
| Area in a 30 t load | 555.6m² |
Mass per square metre is thickness times density: 54 kg/m² for 20 mm granite and 81 for 30 mm, and those two numbers set both haulage and the dry-hung framing. Stone is famously heavier than it looks — a 600 × 600 at 30 mm is 29 kg per piece.
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Formula
| Area | A = length × width in metres |
| Volume | V = A × thickness in metres |
| Mass per piece | V × density × 1000 |
| Mass per m² | thickness (mm) × density |
| Total | per piece × quantity |
| Truck load | area = payload × 1000 ÷ mass per m² |
Fifty 600 × 300 × 20 mm granite pieces: 0.180 m², 0.0036 m³ and 9.72 kg each — 9.000 m² and 486.00 kg in total, about 103 pieces to the tonne.
How to work it out
- Fix the stone type and density: granite 2.7-2.8 g/cm³, marble 2.6-2.7, sandstone 2.2-2.5, slate 2.7-2.8, engineered stone 2.3-2.5.
- Volume per piece = length × width × thickness in metres, multiplied by density for the weight.
- Multiply by the count. Natural stone varies 3-5% between batches from one quarry, so measure on critical work.
- Weight per m² = thickness in mm × density. A 20 mm granite is 54 kg/m² — the figure that drives dry-hang and adhesive selection.
- Dry hanging also needs bracket checks: a 0.9 × 0.9 m 25 mm granite panel weighs 55 kg, so four brackets each carry about 14 kg plus wind.
Where it goes wrong
- Using 2.7 for all stone — marble is 2.6-2.7 and sandstone 2.2-2.5, so sandstone comes out 20% heavy; that inflates the quote and the lifting plan.
- Using dry density where the stone will be wet — absorption is 0.2-2% and saturated stone is 1-2% heavier, so use saturated density outdoors.
- Using nominal thickness — stone is toleranced ±1-2 mm and a nominal 20 mm panel often measures 18.5, which is 8% light.
- Ignoring backing mesh and adhesive — thin panels are mesh-backed, adding 2-4 kg/m², which matters over large dry-hung areas.
Material and cost
Granite 200-600 CNY/m² (common 200-300, imported or special 500+), marble 400-1200, sandstone 150-400. Fabrication such as edge polishing, grooving and undercut holes 20-60 CNY/m.
On site
- Stone is heavy: a dry-hung stone facade loads 50-70 kg/m², double a glass facade at 25-40, so structure and anchors must be sized for it.
- Keep one quarry and one batch across a project; density, colour and veining all shift between quarries.
- Allow for hoisting: crane and hoist rated loads fill quickly with stone, since a single large panel can weigh hundreds of kilograms.
Basis
- GB/T 18601-2009 Natural granite slabs for building
- GB/T 19766-2016 Natural marble slabs for building
- JGJ 133-2001 Technical code for metal and stone curtain walls, Section 3.2
FAQ
Why do stone deliveries keep overloading?
Because loading by volume badly overshoots on weight. Granite 30 mm is 81 kg/m², so a 30 t truck takes 370 m² of slab; load 400 m² by eye and you are 2.4 t over. Always plan by payload: 370 m² of 30 mm is the ceiling on a 30 t truck.
How does thickness differ between wet-fix and dry-hung?
Wet fixing on cement mortar uses 18-20 mm and relies on full-bed adhesion; dry hanging uses 25-30 mm carried by stainless brackets and framing, with slots or holes cut in the slab. Dry-hung stone under 25 mm cracks at the slot, and wet-fixed stone over 25 mm is heavy enough to debond as the mortar shrinks — wet fixing is barred on tall facades.
How much heavier is granite than marble?
Three to eight percent. Granite runs 2.7-2.8, marble 2.6-2.8, sandstone only 2.2-2.4 and engineered stone 2.3-2.5. At 20 mm that is 54 kg/m² for granite, 53 for marble and 46 for sandstone. Outdoors must be granite — marble weathers badly and acid rain dulls and yellows it.
Cite this page
Use this format in reports, method statements or coursework. The link is permanent.
Building Calculator. Stone Weight Calculator. 2026-10-25. https://jianzhujisuan.com/en/stone-weight
Results are estimating aids only and are not a design basis. Construction and final accounts must follow the drawings, the applicable standards and an approved method statement. Anything affecting structural safety, shoring or falsework must be checked by a suitably qualified engineer.